1. Field of the Invention
The present invention relates to a rear axle apparatus for a tractor having a rear axle case and brake structure. More particularly, the invention relates to a structure including brakes arranged relative to rear axle cases to brake rotation of differential gear shafts.
2. Description of the Related Art
This type of structure provided around rear axles of a tractor is disclosed in Japanese Utility Model Publication No. 1988-128135, for example. FIG. 8 shows a principal portion of the structure disclosed in the above publication. As seen, the prior structure includes what is called a brake case 51 mounted between a transmission case 50 and a rear axle case 52. The brake case 51 has a brake support 56 formed as an inward and integral part thereof for contacting brake disks rotatable with a differential gear shaft. A planetary reduction mechanism 53 has an internal gear 54 fixedly mounted between the brake case 51 and rear axle case 52.
The above prior structure includes what is called a brake case, formed separately from the rear axle case, for supporting or defining a brake support. Thus, the prior structure is complicated with a large number of components, which results in high cost.
When it is desired to manufacture a modified version of the above structure with an increased number of brake disks, for example, a change in the position of a supporting surface of the brake support becomes imperative. Such a modification is possible only by manufacturing a new brake case having a brake support of different shape or disk receiving position. It is unreasonable and costly to design and manufacture a large component such as a brake case all over again just to increase the number of brake disks. Thus, improvement has been desired.